Visually, the "extreme" outliers in the following graph are somewhat obvious:
- T - Set of all temperatures
- Y - Set of all years
- ΣT - Sum of temperatures.
- ΣY - Sum of years.
- N - Number of elements
- T(n) - Temperature of the nth element in the temperature set
How do you determine if T(n) is an outlier?
The math on some of these sites is a bit above my understanding:
- Multiple Outliers Detection Procedures in Linear Regression (broken link)
- Measure of Surprise for Outlier Detection
- Ordinary Least Squares Linear Regression